Shaped charges



Sept. 18, 1956 J. H. CHURCH ETAL SHAPED CHARGES Filed Jan. 6, 1955 x7 0 2: 1 3 1 W i 1 I v L M I t f l I Z9 f9 INVENTORSI Jclaph HJIhurch h BY Gregor-H .llKe-ssamc nite States SHAPED CHARGES Joseph H. Church, Austin, Mind, and Gregory J. Kessenich, Madison, Wis., assignors to the United States of America as represented by the Secretary of the Army The invention described herein may be manufactured and used by or for the Government, for governmental purposes, without the payment to us of any royalty thereon.

This application is a continuation in part of our pending application Serial No. 158,583, filed April 27, 1950 for shaped charges, now abandoned.

A principal object of our invention is to provide an externally shaped charge provided with a cavity arrangement which will achieve maximum directed force eifect, thereby rendering practical the use of such externally shaped charge which by virtue of the external shape thereof is especially adapted to use in restricted areas.

Other objects will become apparent from the followlng description when considered with the appended drawing, in which: I

Figure 1 is a section taken in a plane identified by l1ne 11, Figure 2, showing a shaped charge in accordance with our invention; and

Figure 2 is a front elevation of the charge shown in Figure 1.

In Figure 1 we have shown a shaped charge confined within a thin walled casing externally configured in accordance with our invention and which is externally defined by the coaxial cylindrical surfaces 11 and 12 joined by upper and lower fiat ends or side walls 13 and 14, respectively. The charge 10 may be a complete annulus or only a portion of an annulus as shown, in wh1ch latter form the end surfaces 15 are arranged as shown in Figure 1, in plates intersecting in a line parallel with and adjacent the axis 25. u

The concave cylinder surface 11 forms the primary cavity 16 of the charge and for the purpose of accentuating or augmenting the directed effect caused by the primary cavity upon detonation of charge 10, secondary cavities 17 are formed in surface 11 toward the surface 12 of greater diameter. The cavities 17 may be of any symmetric form and are arranged to he in equally angularly spaced radial planes through the common axis 25 of the coaxial cylindrical surfaces 11 and 12.

A liner 18 of any appropriate metallic or non-metallic material such as copper, aluminum, or synthetic plastic, fit the cavities 16 and 17 as shown. The liner 18 may be retained in position by the end walls 19 which, together with convex wall 21 and side walls 13, 14, completely encases the charge except for the shaped cavities therein.

The end walls 19 is dimensioned to afiord space for a booster charge between the main charge 10 and the convex wall of the casing. As shown, this convex wall carries a plurality of detonators 20a. Each detonator lies in the plane of symmetry of a respective secondary recess, which plane contains the axis of the surfaces 11 and 12.

Means such as a source of voltage 22, electricallyinitiated detonators 20a and parallel circuit connections 23 are provided to simultaneously initiate the detonators or fuzes.

When the detonators 20a are simultaneously initiated by closure of switch 24, the secondary lined cavities collapse at the same instant and create jets, shock waves and slugs of liner material which reinforce and augment the penetrative power of the shock waves and slug resulting from the collapse of the main cavity. Applicants are not certain as to the exact reasons for the superior penetration and destructive effect, weight for weight of explosive, of their invention. It may be due to the greater mass of the liner resulting from secondary cavities 17, or it may be due to the simultaneous initiation of the secondary jets and slugs a microsecond or two in advance of the collapse of the main cavity, or to a combination of the two phenomena. This uncertainty is due to the fact that quantitative measurements in this art are very diflicult due to the extremely small times involved necessarily measured in microseconds, as well as to the tremendous forces and temperatures.

While we have shown the preferred form of our invention as now known to us, various changes in shapes, sizes, relations and arrangement of elements will occur to those skilled in this art after a study of the foregoing disclosure. Hence such disclosure is to be taken in an illustrative rather than a limiting sense.

Having now fully disclosed the invention, we claim:

1. In an explosive unit, a solid shaped explosive charge having a convex side wall formed as a surface of revolution about an axis and a main cavity having a second surface of revolution about said axis and of lesser radius than said convex wall, there being secondary cavities in said main cavity, each secondary cavity being symmetrical about a respective one of a corresponding number of equiangularly spaced planes through said axis, and a plurality of detonators in detonating relation with said convex side wall, each said detonator lying in a respective one of said equiangularly spaced planes.

2. In an explosive shaped charge unit, a casing having a convex wall comprising a surface of revolution about an axis, angularly related end walls lying in respective planes intersecting in a line in the median plane of symmetry of said unit adjacent and substantially parallel with said axis and side walls spaced along said axis normal thereto, a shaped explosive charge filling said casing and having a main cavity therein defining a second surface of revolution about said axis, there being secondary cavities in the surface of said main cavity, each symmetrical with respect to a respective one of a plurality of equiangularly spaced planes through said axis, a liner fitting said main cavity and the secondary cavities therein and closing said casing, and a plurality of detonators carried by said side wall in detonating relation with said charge, each said detonators lying in a respective one of said equiangularly spaced planes.

3. In an explosive shaped charge unit, a casing having a convex wall comprising a cylindrical surface symmetrical about an axis, angularly related end walls in respective planes intersecting in a line in the median plane of symmetry of said unit adjacent to and substantially parallel with said axis and spaced parallel side walls substantially normal to said axis, a shaped explosive charge filling said casing and having a main cylindrical cavity coaxial with said axis, there being a plurality of secondary cavities in said main cavity each symmetrical with respect to a respective one of a plurality of equiangularly related planes through said axis, a metallic liner fitting said main and secondary cavities and closing said casing, a plurality of detonators fixedly carried by said side wall, each detonator lying in a respective one of said equiangularly related planes, and means operable to simultaneously initiate all of said detonators.

4. In an explosive unit, a regularly-shaped solid charge of explosive defined by the space between (1) two coaxial cylindrical surfaces of greater and lesser radii, (2) two angularly-related planes substantially through the common axis of said surfaces and intersecting the same and (3) two spaced parallel planes normal to said axis, there being a plurality of cavities in said surface of lesser radius, each said cavity being symmetrical with respect to a respective one of a plurality of equi-angularly spaced radial planes through the common axis of said cylindrical surfaces, a thin-walled container enclosing said charge and including a metallic liner fitting said surface of lesser radius and the cavities therein, and a plurality of detonators carried by that portion of said container over said cylindrical surface of greater radius and in detonating relation with said charge of explosive, each said detonator lying in the radial plane with a respective one of said cavities.

5. In a shaped charge unit, an improvement comprising, the combination of a main explosive charge within a casing having a convex wall formed as a surface of revolution about an axis and a main cavity formed by a second surface of revolution about said axis of lesser radius than said convex wall, angularly related end walls lying in respective planes intersecting in a line outwardly contiguous and parallel with said axis within the median plane of said unit through said axis, spaced parallel side Walls substantially normal to said axis, there being a plurality of secondary cavities in said main cavity each symmetrical with respect to a respective one of a plurality of equiangularly related planes through said axis, a metallic liner fitting said main and secondary cavities and closing said casing, there being a booster charge overlying said main explosive intermediate said main explosive and said convex wall, a plurality of detonators carried by said convex wall in detonating relation with said booster, each said detonator being symmetrical about said equi-angular planes, and means operable to simultaneously initiate all of said detonators.

References Cited in the file of this patent UNITED STATES PATENTS 2,587,243 Sweetman Feb. 26, 1952 2,605,704- Durnas Aug. 5, 1952 FOREIGN PATENTS 21,344 Great Britain of 1911 579,279 Great Britain July 30, 1946 

